The purpose of this project is to analyze current data in the fibrin clotting and platelet fields, and to investigate in various ways, including international collaborative studies, the need for reference standards for specific clotting factors for use in potency labelling of products and for diagnostic reagents. Heparin standards are under investigation. Problems of nomenclature in the fields of thrombosis and hemostasis are investigated. Clinical trials of various types to assess evaluation of therapeutic agents may be initiated, especially in the initial pilot stages. A registry for animal models of disease is being developed.